This is an anglicized form of the Olde Gaelic name O Dubhda. The Gaelic prefix "O" indicates "male descendant of", plus the personal name Dubhda, from "dubh" meaning "black". The sept claim descent from Fiacha, brother of Niall of the Nine Hostages, 4th Century King of Ireland, and for centuries the (O) Dowds were the leading sept in the ancient territory of Ui Fiachrach (comprising North Mayo, Sligo and parts of South Galway). Several clan members were bishops of the see of Killala, (Co. Mayo). In the 17th Century many (O) Dowds fought in the army of King James and their chief at that time, killed in the Battle of the Boyne (1690), is reputed to have been seven feet tall. On May 25th 1847 Michael Dowd, who embarked from Sligo, was a famine immigrant into New York. The name is also anglicised as Dowda, Doody, and Duddy. The first recorded spelling of the family name is shown to be that of Sen. Bhrian O'Dowd, chief of Ui Fiachrach, which was dated 1354, he drove Anglo-Norman settlers from his territory, during the reign of King Edward 111, known as "The Father of the Navy", 1327 - 1377. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.